CN110095399A - Reservoir inaccessible pore volume determines method and device - Google Patents

Abstract

The invention provides a method and device for determining the volume of inaccessible pores in a reservoir, wherein the method includes the following steps: obtaining all pore diameter data of the tested reservoir, and arranging all the pore diameter data in ascending order; obtaining polymer Arrange all molecular cluster particle size data in order from small to large; analyze all sorted pore size data and all sorted molecular cluster particle size data, according to different analysis results, Different calculation methods are used to calculate the inaccessible pore volume IPV of the tested reservoir. This scheme directly calculates the inaccessible pore volume IPV based on the particle size distribution of polymer molecular clusters and the reservoir pore size distribution data, and does not need to be measured through indoor displacement experiments, thereby shortening the test time, saving test costs, and improving test accuracy.

Description

Method and device for determining inaccessible pore volume of reservoir

technical field

The invention relates to the technical field of petroleum engineering, in particular to a method and device for determining the volume of inaccessible pores in a reservoir.

Background technique

Polymer flooding is an important enhanced oil recovery technology. It enhances oil recovery by injecting a polymer solution into the reservoir to improve the mobility ratio. The polymer molecules in the solution are flexible polymer groups with a certain radius of gyration. When this molecular group migrates in the porous medium, it can only enter a part of the pores with a larger pore size, and the remaining part of the pores cannot enter. Inaccessible Pore Volume (IPV for short) refers to the proportion of the pore volume that is inaccessible to external media to the total pore volume. The existence of IPV will reduce the sweep range of polymer flooding, which is not conducive to the improvement of oil recovery. When formulating a polymer flooding plan, the IPV of the reservoir is an important parameter. Accurate and simple determination of IPV is of great significance for polymer molecular weight screening and polymer solution dosage optimization.

At present, IPV is determined by indoor displacement experiments. In Patent 1 (Application No.: CN201510039318.5, Patent Name: "Method for Determination of Inaccessible Pore Volume and Inaccessible Pore Radius of Polymers"), the pore volume minus the polymer volume remaining in the pores is the polymer volume. IPV. Wherein, the volume of the polymer retained in the pores is equal to the difference between the total volume of the injected polymer and the total volume of the produced polymer. The output polymer volume is equal to the sum of the polymer volumes contained in each output liquid. The polymer concentration in the output fluid should decrease continuously, but this patent regards the polymer concentration in the output fluid as a step-like discrete decrease, so there is a significant error in the IPV obtained by the patent.

Document 1 (an article "A New Method for Calculating the Inaccessible Pore Volume of Polymer Flooding" published in the Journal of Jianghan Petroleum Institute, Volume 17, Phase 2, Pages 56-59 in June 1995) utilizes semi-permeable barrier method or The IPV of polymer flooding is calculated from the capillary pressure curve of oil flooding water measured by centrifuge method. This method involves the flow index of the polymer solution and the tortuosity of the reservoir, but these two parameters need to be determined through experiments, and the test errors are relatively large. Documents 2-5 (Document 2 is the article "Impenetrable Pore Volume Effect of Modified Starch Polymer Solution in Porous Media" published in Fault Block Oil and Gas Field Journal, Volume 17, Issue 6, Pages 755-758 in November 2010, Document 3 is the article "Inaccessible Pore Volume and Related Properties of Xinjiang Outcrop Cores" published in Oilfield Chemistry Journal Vol. The article "Determining Impenetrable Pore Volume and Residual Pore Volume Using Polymer Flooding Production Fluid Concentration Profile Model" in the Journal of Petroleum Geology and Recovery, Vol. The article "Inaccessibe Pore Volume in Polymer Flooding" published on pages 488-452 of the Society of Petroleum Engineers Journal) proposes that the relationship between the material balance of the injected solution's breakthrough front edge, the breakthrough trailing edge, the polymer trailing edge, and the trailing edge flow curve can be used. The envelope area and other four methods determine the IPV of polymer flooding. Some methods have the disadvantages of long period and high cost because a large number of experiments are required; other methods are not accurate enough because of the lack of standard experimental test procedures and uncertainty in the interpretation of test results.

Contents of the invention

The embodiment of the present invention provides a method and device for determining the inaccessible pore volume of a reservoir, which solves the technical problem in the prior art that the test accuracy of the inaccessible pore volume IPV is not high.

The method for determining the inaccessible pore volume of the reservoir provided by the embodiment of the present invention includes:

Obtain all pore diameter data of the tested reservoir, and arrange all pore diameter data in ascending order;

Obtain the particle size data of all molecular clusters of the polymer, and arrange the particle size data of all molecular clusters in order from small to large;

Analyze all sorted pore size data and sorted molecular cluster particle size data:

When all the sorted pore size data and the sorted molecular cluster particle size data are discrete, the inaccessible pore volume IPV is calculated as follows:

Calculate the IPV value probability distribution law corresponding to each pore diameter data;

Calculate the IPV value corresponding to each pore diameter data point according to the molecular cluster particle size critical value corresponding to each pore diameter and all molecular cluster particle size data;

Calculate the inaccessible pore volume IPV of the test reservoir according to the IPV value probability distribution law corresponding to each pore diameter data point and the IPV value corresponding to each pore diameter data point;

When the interval and distribution frequency of pore diameter and the interval and distribution frequency of molecular cluster particle size are obtained through analysis, the inaccessible pore volume IPV is calculated as follows:

According to the distribution frequency of each pore diameter interval, calculate the IPV value probability distribution law corresponding to each pore diameter interval;

Calculate the IPV value corresponding to each pore diameter interval according to the critical value of the molecular cluster particle size interval corresponding to each pore aperture interval and the distribution frequency of all molecular cluster particle diameter intervals;

According to the IPV value probability distribution law corresponding to each pore diameter interval and the IPV value corresponding to each pore diameter interval, calculate the inaccessible pore volume IPV of the test reservoir;

When the distribution probability density function of the pore diameter and the distribution probability density function of the particle size of the molecular cluster are obtained through analysis, the inaccessible pore volume IPV is calculated as follows:

According to the distribution probability density function of the pore diameter, calculate the IPV value probability density function corresponding to any pore diameter;

According to the critical value of molecular cluster particle size corresponding to any pore size and the distribution probability density function of molecular cluster size, calculate the IPV value corresponding to any pore size;

According to the IPV value probability density function corresponding to any pore diameter and the IPV value corresponding to any pore diameter, the inaccessible pore volume IPV of the test reservoir is calculated.

The device for determining the volume of inaccessible pores in reservoirs provided by the embodiments of the present invention includes:

The pore diameter data acquisition module is used to obtain all the pore diameter data of the test reservoir, and arrange all the pore diameter data in ascending order;

The molecular cluster particle size data acquisition module is used to obtain all the molecular cluster particle size data of the polymer, and arrange all the molecular cluster particle size data in ascending order;

The analysis module is used to analyze all the pore size data after sorting and the particle size data of all molecular clusters after sorting;

The inaccessible pore volume IPV calculation module is used for:

When all the sorted pore size data and the sorted molecular cluster particle size data are discrete, the inaccessible pore volume IPV is calculated as follows:

Calculate the IPV value probability distribution law corresponding to each pore diameter data;

Calculate the IPV value corresponding to each pore diameter data point according to the molecular cluster particle size critical value corresponding to each pore diameter and all molecular cluster particle size data;

Calculate the inaccessible pore volume IPV of the test reservoir according to the IPV value probability distribution law corresponding to each pore diameter data point and the IPV value corresponding to each pore diameter data point;

When the interval and distribution frequency of pore diameter and the interval and distribution frequency of molecular cluster particle size are obtained through analysis, the inaccessible pore volume IPV is calculated as follows:

According to the distribution frequency of each pore diameter interval, calculate the IPV value probability distribution law corresponding to each pore diameter interval;

Calculate the IPV value corresponding to each pore diameter interval according to the critical value of the molecular cluster particle size interval corresponding to each pore aperture interval and the distribution frequency of all molecular cluster particle diameter intervals;

According to the IPV value probability distribution law corresponding to each pore diameter interval and the IPV value corresponding to each pore diameter interval, calculate the inaccessible pore volume IPV of the test reservoir;

When the distribution probability density function of the pore diameter and the distribution probability density function of the particle size of the molecular cluster are obtained through analysis, the inaccessible pore volume IPV is calculated as follows:

According to the distribution probability density function of the pore diameter, calculate the IPV value probability density function corresponding to any pore diameter;

According to the critical value of molecular cluster particle size corresponding to any pore size and the distribution probability density function of molecular cluster size, calculate the IPV value corresponding to any pore size;

According to the IPV value probability density function corresponding to any pore diameter and the IPV value corresponding to any pore diameter, the inaccessible pore volume IPV of the test reservoir is calculated.

An embodiment of the present invention also provides a computer device, including a memory, a processor, and a computer program stored on the memory and operable on the processor, and the processor implements the above-mentioned method when executing the computer program.

An embodiment of the present invention also provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program for executing the above method.

In the embodiment of the present invention, all the pore diameter data of the test reservoir are obtained, and all the pore diameter data are arranged in order from small to large; Arrange to the largest order; analyze all the sorted pore diameter data and all sorted molecular cluster particle size data, and use different calculation methods to calculate the inaccessible pore volume IPV of the test reservoir according to different analysis results. This scheme directly calculates the inaccessible pore volume IPV based on the particle size distribution of polymer molecular clusters and the reservoir pore size distribution data, and does not need to be measured through indoor displacement experiments, thereby shortening the test time, saving test costs, and improving test accuracy.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a flow chart of a method for determining the volume of inaccessible pores in a reservoir provided by an embodiment of the present invention;

Fig. 2 is a schematic diagram of a core pore size distribution and a polymer molecular cluster particle size distribution provided by an embodiment of the present invention;

Figure 3 is a schematic diagram of a multi-diameter pore core and multi-diameter polymer molecular clusters provided by an embodiment of the present invention;

Fig. 4 is a kind of pore size and particle size distribution figure provided by the embodiment of the present invention;

Fig. 5 is an aperture interval distribution frequency diagram provided by an embodiment of the present invention;

Fig. 6 is a particle size interval distribution frequency diagram provided by an embodiment of the present invention;

Fig. 7 is an aperture distribution frequency diagram provided by an embodiment of the present invention;

Fig. 8 is a structural block diagram of a device for determining the volume of inaccessible pores in a reservoir provided by an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The formation of oil and gas reservoirs is the result of the joint action of various random events (such as geological movement, deposition, compaction, cementation, and dolomitization). Its pore distribution is random. Let the random variable x represent the core pore diameter (hereinafter referred to as pore diameter). Polymer molecular weight is not a constant value, its distribution is random. The hydrodynamic diameter of the flexible molecular group in the polymer solution has a one-to-one correspondence with the molecular weight of the polymer, that is, the distribution of the hydrodynamic diameter of the molecular group in the polymer solution is not uniform, but also random. Let the random variable y represent the hydrodynamic diameter of the polymer molecular cluster (hereinafter referred to as the particle diameter).

Let the critical value of particle size corresponding to the pore with pore size x be Ω(x). For polymer molecular clusters with uniform particle size y and core pores with uniform pore diameter x, when y≤Ω(x), there will be molecular clusters in all pores that can enter, and IPV=0.0 at this time; when y>Ω( When x), all pores cannot enter molecular clusters, and at this time IPV=1.0. The pore diameters of actual reservoir cores are not uniform, but randomly distributed within a certain range [x _min ,x _max ]. The particle size of molecular clusters in the actual polymer solution is not uniform, but randomly distributed within a certain range [y _min ,y _max ]. In the polymer solution slugs prepared in different batches, the positions of the molecular clusters were randomly distributed. Even in slugs of polymer solutions prepared in the same batch, the positions of molecular clusters are randomly distributed. Obviously, the process of these randomly distributed molecular clusters passing through the pores of the reservoir core is a random event. Therefore, the essence of IPV calculation is to determine the probability of pore size and particle size mismatch (y>Ω(x)). This means that the IPV obtained by each experimental test may be different. This is also the biggest flaw of the experimental testing method. Due to the limited number of experimental tests due to time, manpower, material and financial costs, it is impossible to obtain accurate inaccessible pore volumes.

Essentially, reservoir IPV is caused by a mismatch between polymer cluster size and pore size. Reservoir pore size distribution is an essential data in oilfield development, which can be measured by specific surface and pore size analyzer or by mercury injection experiment. The molecular weight of the polymer is measured by gel permeation chromatography or laser particle size analyzer. The particle size of a polymer molecular cluster is represented by its hydrodynamic diameter, and the hydrodynamic diameter can be calculated based on the molecular weight of the polymer through the average distance equation between two endpoints proposed by Flory. Since the test methods of specific surface and pore size analyzer, gel permeation chromatography or laser particle size analyzer are relatively mature, the test results have high precision. Based on this, based on the principle of probability theory, the present invention uses the reservoir pore size distribution data commonly used in oil fields and the polymer molecular gyration diameter distribution data to establish a set of methods and devices for determining the volume of inaccessible pores in reservoirs. The IPV can be directly calculated from the diameter distribution and reservoir pore size distribution data, and there is no need to measure it through indoor displacement experiments, thereby shortening the test time, saving test costs and improving test accuracy.

In the embodiment of the present invention, as shown in FIG. 1, the method for determining the volume of inaccessible pores in the reservoir includes:

Step 101: Obtain all the pore diameter data of the test reservoir by using a specific surface and pore diameter analyzer or through a mercury intrusion experiment, and arrange all the pore diameter data in ascending order;

Step 102: The molecular weight of the polymer is measured by gel permeation chromatography or laser particle size analyzer, and the Flory method is used to calculate the particle size data of all molecular clusters of the polymer, and arrange the particle size data of all molecular clusters in order from small to large;

Step 103: Analyze all sorted pore size data and sorted particle size data of all molecular clusters:

Step 104: When the analysis obtains that the sorted pore size data and the sorted molecular cluster particle size data are all discrete, the inaccessible pore volume IPV is calculated in the following manner:

Calculate the IPV value probability distribution law corresponding to each pore diameter data;

Calculate the IPV value corresponding to each pore diameter data point according to the molecular cluster particle size critical value corresponding to each pore diameter and all molecular cluster particle size data;

Calculate the inaccessible pore volume IPV of the test reservoir according to the IPV value probability distribution law corresponding to each pore diameter data point and the IPV value corresponding to each pore diameter data point;

Step 104: When the interval and distribution frequency of pore diameters and the interval and distribution frequency of molecular cluster particle diameters are obtained through analysis, the inaccessible pore volume IPV is calculated in the following manner:

According to the distribution frequency of each pore diameter interval, calculate the IPV value probability distribution law corresponding to each pore diameter interval;

Calculate the IPV value corresponding to each pore diameter interval according to the critical value of the molecular cluster particle size interval corresponding to each pore aperture interval and the distribution frequency of all molecular cluster particle diameter intervals;

According to the IPV value probability distribution law corresponding to each pore diameter interval and the IPV value corresponding to each pore diameter interval, calculate the inaccessible pore volume IPV of the test reservoir;

Step 104: When the distribution probability density function of the pore diameter and the distribution probability density function of the particle size of the molecular cluster are obtained through analysis, the inaccessible pore volume IPV is calculated in the following manner:

According to the distribution probability density function of the pore diameter, calculate the IPV value probability density function corresponding to any pore diameter;

According to the critical value of molecular cluster particle size corresponding to any pore size and the distribution probability density function of molecular cluster size, calculate the IPV value corresponding to any pore size;

According to the IPV value probability density function corresponding to any pore diameter and the IPV value corresponding to any pore diameter, the inaccessible pore volume IPV of the test reservoir is calculated.

In this embodiment of the present invention, a simple example is given. Suppose a rock core with a length L is composed of 3 pores (see the left figure in Fig. 2), and the pore diameters are x ₁ = 50 μm, x ₂ = 28 μm and x ₃ = 20 μm; the polymer solution contains 5 molecular groups (See the figure on the right side of Figure 2), and the particle diameters are y ₁ (one molecular group), y ₂ (three molecular groups) and y ₃ (one molecular group). In this example, molecular clusters with particle size y ₁ can only enter pores with pore size x ₁ , molecular clusters with particle size y ₂ can only enter pores with pore sizes x ₁ and x ₂ , and molecular clusters with particle size y ₃ Molecular groups can enter all pores.

The ratio of the pore volume with pore diameter x _i to the total pore volume of the core (equivalent to the probability distribution law of discrete random variables for:

Among them, φ ₁ = 0.6786; φ ₂ = 0.2128; φ ₃ = 0.1086; x _a is the a-th pore diameter data; a = 1,2,3;

Given that all molecular clusters can enter the pore with a diameter of x ₁ , the probability that no molecular cluster enters the pore (equivalent to the discrete value of the discrete random variable) is: P ₁ =0;

Given that only y ₁ molecular clusters cannot enter a pore with a pore size of x ₂ , the probability that no molecular cluster enters this pore (equivalent to the discrete value of a discrete random variable) is:

Given that neither y ₁ nor y ₂ molecular clusters can enter the pore with a diameter of x ₃ , the probability that no molecular cluster enters the pore (equivalent to the discrete value of a discrete random variable) is:

If molecular cluster y ₁ just enters pore x ₁ , molecular cluster y ₂ corresponds to pore x ₂ , and molecular cluster y ₃ corresponds to pore x ₃ , then molecular clusters enter all three pores, that is, P ₁ ＝ P ₂ ＝ P ₃ =0, then If the y ₃ molecular cluster corresponds to the x ₁ pore, the y ₁ molecular cluster corresponds to the x ₂ pore, the y ₂ molecular cluster corresponds to the x ₃ pore, only the x ₁ pore has the molecular cluster entering, and the x ₂ and x ₃ pores do not Molecular group enters, that is, P ₁ =0, P ₂ =P ₃ =1, then For this example, the IPV determined by the displacement experiment should be a random value in the interval [0,0.3214]. According to the principle of probability theory, as the number of experimental tests increases, IPV will approach its mathematical expectation value, which is a constant value

Based on the above, the present invention proposes the above-mentioned method, which calculates the inaccessible pore volume IPV according to the multi-diameter pore core (see the figure on the left in Figure 3) and the polymer molecules with multiple particle diameters (see the figure on the right in Figure 3). Specifically, three different calculation methods (described in step 104) are proposed.

One of the calculation methods:

Assuming that the measured data points are N pore size data points, which are arranged in order from small to large, it can be obtained that x _min = x ₁ ≤ x ₂ ≤...≤ x _N ≤ x _max ; assuming that the measured data points are M particle size data points, Arranged in descending order, it can be obtained that y _min =y ₁ ≤y ₂ ≤...≤y _M ≤y _max .

For any pore diameter x _i , the proportion of the volume of this part of the pores to the total pore volume of the core is:

Obviously, The essence of this ratio φ _i is the probability distribution law of its IPV value.

Let the critical value of the particle size corresponding to the pores with the pore size x _i be Ω( _xi ), and Then the number of polymer molecular groups greater than or equal to Ω( _xi ) is MK _i , and K _i is the serial number of the particle size critical value corresponding to the i-th pore size data point among all the particle size data points. These molecular clusters will not be able to enter the pores with a pore size of _xi .

For any pore diameter x _i , the IPV value of this part of the pore (that is, the probability that no molecular cluster enters) is:

The inaccessible pore volume IPV is:

According to the relevant literature, the particle diameter critical value corresponding to the pore size x _i is Ω( _xi )=0.2x _i .

Calculation method two:

Assume that the actual measurements are N aperture intervals and their distribution frequencies, the interval mean is x _min ＝x ₁ ≤ x ₂ ≤...≤x _N ≤ x _max , and the distribution frequency of each interval is f( _xi ); are M particle size intervals and their distribution frequency, the interval homogeneity is y _min =y ₁ ≤y ₂ ≤...≤y _M ≤y _max , and the distribution frequency of each interval is g(y _j ).

For any pore diameter interval x _i , the proportion of the volume of this part of the pores to the total pore volume of the core is:

Obviously, The essence of this ratio φ _i is the probability distribution law of the IPV value, x _a is the a-th pore diameter data, a=1,2,...,N.

Let the critical value of the particle size corresponding to the pores with the pore size x _i be Ω( _xi ), and These molecular clusters will not be able to enter the pores with a diameter of x _i .

For any pore size interval x _i , the IPV value of this part of the pore (that is, the probability that no molecular cluster enters) is:

The inaccessible pore volume IPV is:

The calculation method three:

Assume that the actual measurement is the probability density function F(x) of the pore size data in a certain range [x _min , x _max ]; suppose that the actual measurement is the probability that the particle size data is in a certain range [y _min , y _max ] Density function G(y). In this case, both pore size x and particle size y are continuous random variables.

For any pore diameter x, the probability density function of this part of the pore IPV value is:

in, Obviously,

Let the critical value of particle size corresponding to the pore with pore size x be Ω(x). If y≥Ω(x), these molecular clusters will not be able to enter the pores with a diameter of x.

For any pore diameter x, the IPV value of this part of the pore (that is, the probability that no molecular cluster enters) is:

The inaccessible pore volume IPV is:

The method of the present invention is illustrated below through specific examples.

(1) Example #1

According to the pore diameter data of a certain reservoir and the hydrodynamic particle size data of the polymer molecular clusters used (see Table 1 for the measured data), a total of 211 data points were measured. The pore size and particle size distribution diagrams are shown in Figure 4. According to calculation method 1 of the present invention, the calculated inaccessible pore volume of polymer molecules is 0.1626.

Table 1 Measured pore size and particle size data table

(2) Example #2

A total of 100 data points were measured according to the interval distribution data of the pore diameter of a certain reservoir and the interval distribution data of the hydrodynamic particle size of polymer molecular clusters (see Table 2 for the measured data). The distribution frequency of pore size interval and particle size interval is shown in Fig. 5 and Fig. 6. According to the second calculation method of the present invention, the calculated inaccessible pore volume is 0.4831.

Table 2 Distribution frequency table of pore size interval and particle size interval

(3) Example #3

The probability density function of the pore diameter of a reservoir in the interval [4.0μm, 80.0μm] is F(x)=(-x ² +84x-320)/73162.67; the hydrodynamic particle size of polymer molecular clusters is in the interval [ The probability density function within 2.0 μm, 20.0 μm] is G(y)=(-y ² +22y-40)/972. The pore size and particle size probability density functions are shown in Fig. 7. According to the third calculation method of the present invention, the calculated inaccessible pore volume is 0.5137.

Based on the same inventive concept, an embodiment of the present invention also provides a device for determining the volume of inaccessible pores in a reservoir, as described in the following embodiments. Since the problem-solving principle of the reservoir inaccessible pore volume determination device is similar to the reservoir inaccessible pore volume determination method, the implementation of the reservoir inaccessible pore volume determination device can refer to the implementation of the reservoir inaccessible pore volume determination method, and repeat I won't repeat them here. As used below, the term "unit" or "module" may be a combination of software and/or hardware that realizes a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementations in hardware, or a combination of software and hardware are also possible and contemplated.

Fig. 8 is a structural block diagram of a device for determining the volume of inaccessible pores in reservoirs according to an embodiment of the present invention, as shown in Fig. 8, including:

The pore diameter data acquisition module 801 is used to obtain all the pore diameter data of the test reservoir, and arrange all the pore diameter data in ascending order;

Molecular cluster particle size data acquisition module 802, used to obtain all molecular cluster particle size data of the polymer, and arrange all molecular cluster particle size data in ascending order;

An analysis module 803, configured to analyze all sorted pore size data and sorted particle size data of all molecular clusters;

The inaccessible pore volume IPV calculation module 804 is used for:

When all the sorted pore size data and the sorted molecular cluster particle size data are discrete, the inaccessible pore volume IPV is calculated as follows:

Calculate the IPV value probability distribution law corresponding to each pore diameter data;

Calculate the IPV value corresponding to each pore diameter data point according to the molecular cluster particle size critical value corresponding to each pore diameter and all molecular cluster particle size data;

Calculate the inaccessible pore volume IPV of the test reservoir according to the IPV value probability distribution law corresponding to each pore diameter data point and the IPV value corresponding to each pore diameter data point;

When the interval and distribution frequency of pore diameter and the interval and distribution frequency of molecular cluster particle size are obtained through analysis, the inaccessible pore volume IPV is calculated as follows:

According to the distribution frequency of each pore diameter interval, calculate the IPV value probability distribution law corresponding to each pore diameter interval;

Calculate the IPV value corresponding to each pore diameter interval according to the critical value of the molecular cluster particle size interval corresponding to each pore aperture interval and the distribution frequency of all molecular cluster particle diameter intervals;

According to the IPV value probability distribution law corresponding to each pore diameter interval and the IPV value corresponding to each pore diameter interval, calculate the inaccessible pore volume IPV of the test reservoir;

When the distribution probability density function of the pore diameter and the distribution probability density function of the particle size of the molecular cluster are obtained through analysis, the inaccessible pore volume IPV is calculated as follows:

According to the distribution probability density function of the pore diameter, calculate the IPV value probability density function corresponding to any pore diameter;

According to the critical value of molecular cluster particle size corresponding to any pore size and the distribution probability density function of molecular cluster size, calculate the IPV value corresponding to any pore size;

According to the IPV value probability density function corresponding to any pore diameter and the IPV value corresponding to any pore diameter, the inaccessible pore volume IPV of the test reservoir is calculated.

In the embodiment of the present invention, the inaccessible pore volume IPV calculation module 804 is specifically used for: when all the sorted pore diameter data and the sorted particle size data of all the molecular clusters are discrete after analysis, the above calculation method is used The formula mentioned in 1 calculates the inaccessible pore volume IPV.

In the embodiment of the present invention, the inaccessible pore volume IPV calculation module 804 is specifically used for: when the interval and distribution frequency of pore diameters and the interval and distribution frequency of molecular cluster particle diameters are obtained through analysis, the calculation method 2 mentioned above The derived formula calculates the inaccessible pore volume IPV.

In the embodiment of the present invention, the inaccessible pore volume IPV calculation module 804 is specifically used for: when the distribution probability density function of the pore diameter and the distribution probability density function of the particle size of the molecular cluster are obtained through analysis, the calculation method 2 mentioned above is adopted. The derived formula calculates the inaccessible pore volume IPV.

An embodiment of the present invention also provides a computer device, including a memory, a processor, and a computer program stored on the memory and operable on the processor, and the processor implements the above-mentioned method when executing the computer program.

An embodiment of the present invention also provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program for executing the above method.

In summary, the method and device for determining the volume of inaccessible pores in reservoirs proposed by the present invention is a direct method for determining the volume of inaccessible pores based on particle size and pore size data. Its characteristics are: (1) the required data is easy to obtain, and the accuracy is high; (2) it is simple and easy to implement, and no laboratory test is required; (3) the calculation results are highly reliable. The invention determines the inaccessible pore volume based on the joint probability distribution theory of two independent random variables in the probability theory, and provides a reliable basis for the program formulation of profile control, water shutoff or polymer flooding.

Those skilled in the art should understand that the embodiments of the present invention may be provided as methods, systems, or computer program products. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, various modifications and changes may be made to the embodiments of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A method for determining the inaccessible pore volume of a reservoir, characterized in that, comprising: Obtain all pore diameter data of the tested reservoir, and arrange all pore diameter data in ascending order; Obtain the particle size data of all molecular clusters of the polymer, and arrange the particle size data of all molecular clusters in order from small to large; Analyze all sorted pore size data and sorted molecular cluster particle size data: When all the sorted pore size data and the sorted molecular cluster particle size data are discrete, the inaccessible pore volume IPV is calculated as follows: Calculate the IPV value probability distribution law corresponding to each pore diameter data; Calculate the IPV value corresponding to each pore diameter data point according to the molecular cluster particle size critical value corresponding to each pore diameter and all molecular cluster particle size data; Calculate the inaccessible pore volume IPV of the test reservoir according to the IPV value probability distribution law corresponding to each pore diameter data point and the IPV value corresponding to each pore diameter data point; When the interval and distribution frequency of pore diameter and the interval and distribution frequency of molecular cluster particle size are obtained through analysis, the inaccessible pore volume IPV is calculated as follows: According to the distribution frequency of each pore diameter interval, calculate the IPV value probability distribution law corresponding to each pore diameter interval; Calculate the IPV value corresponding to each pore diameter interval according to the critical value of the molecular cluster particle size interval corresponding to each pore aperture interval and the distribution frequency of all molecular cluster particle diameter intervals; According to the IPV value probability distribution law corresponding to each pore diameter interval and the IPV value corresponding to each pore diameter interval, calculate the inaccessible pore volume IPV of the test reservoir; When the distribution probability density function of the pore diameter and the distribution probability density function of the particle size of the molecular cluster are obtained through analysis, the inaccessible pore volume IPV is calculated as follows: According to the distribution probability density function of the pore diameter, calculate the IPV value probability density function corresponding to any pore diameter; According to the critical value of molecular cluster particle size corresponding to any pore size and the distribution probability density function of molecular cluster size, calculate the IPV value corresponding to any pore size; According to the IPV value probability density function corresponding to any pore diameter and the IPV value corresponding to any pore diameter, the inaccessible pore volume IPV of the test reservoir is calculated. 2. The method for determining the inaccessible pore volume of the reservoir as claimed in claim 1, characterized in that, when the analysis obtains all pore diameter data after sorting and all molecular cluster particle size data after sorting are all discrete, the following formula is adopted Calculate the inaccessible pore volume IPV: Among them, N is the number of pore diameter data, i=1,2,...,N, a=1,2,...,N; x _i is the i-th pore diameter data; x _a is the a-th pore diameter data ; φ _i is the IPV value probability distribution law corresponding to the i-th pore diameter data; M is the number of molecular cluster particle size data; P _i is the IPV value corresponding to the i-th pore size data point; K _i is the serial number of the particle size critical value corresponding to the i-th pore size data point in all particle size data points ; IPV is the inaccessible pore volume IPV of the test reservoir. 3. The method for determining the inaccessible pore volume of a reservoir as claimed in claim 1, characterized in that, when analyzing the interval and distribution frequency of the pore diameter and the interval and distribution frequency of the particle size of the molecular cluster, the following formula is used to calculate the inaccessibility Pore volume IPV: Among them, N is the number of pore aperture intervals, i=1,2,...,N, a=1,2,...,N; x _i is the mean data of the i-th pore aperture interval; x _a is the a-th Pore diameter data; φ _i is the IPV value probability distribution law corresponding to the i-th pore diameter interval; f( _xi ) is the distribution frequency of the i-th pore size interval; M is the number of particle size intervals of molecular clusters; P _i is the IPV value corresponding to the i-th pore size interval; K _i is the corresponding The serial number of the particle size critical value in all particle size intervals; y _j is the mean data of the jth molecular cluster particle size interval; g(y _j ) is the distribution frequency of the jth molecular cluster particle size interval; IPV is the test The inaccessible pore volume IPV of the reservoir. 4. The method for determining the volume of inaccessible pores in a reservoir as claimed in claim 1, characterized in that, when the distribution probability density function of the pore diameter and the distribution probability density function of the particle size of the molecular cluster are analyzed, the following formula is used to calculate the inaccessibility Pore volume IPV: Among them, x is the pore diameter data, which is a continuous random variable; φ(x) is the probability density function of the IPV value of any pore diameter; [x _min , x _max ] is the range of the pore diameter; F(x) is the probability density function of the pore diameter within the range [x _min , x _max ]; P(x) is the IPV value of the pore with the pore diameter x; Ω (x) is the critical value of the molecular cluster particle size corresponding to the pore with the pore size x; G(y) is the probability density function of the molecular cluster particle size within the range [y _min , y _max ]; y is the molecular cluster particle size data, is a continuous random variable; IPV is the inaccessible pore volume IPV of the tested reservoir. 5. A device for determining the volume of inaccessible pores in a reservoir, characterized in that it comprises: The pore diameter data acquisition module is used to obtain all the pore diameter data of the test reservoir, and arrange all the pore diameter data in ascending order; The molecular cluster particle size data acquisition module is used to obtain all the molecular cluster particle size data of the polymer, and arrange all the molecular cluster particle size data in ascending order; The analysis module is used to analyze all the pore size data after sorting and the particle size data of all molecular clusters after sorting; The inaccessible pore volume IPV calculation module is used for: When all the sorted pore size data and the sorted molecular cluster particle size data are discrete, the inaccessible pore volume IPV is calculated as follows: Calculate the IPV value probability distribution law corresponding to each pore diameter data; Calculate the IPV value corresponding to each pore diameter data point according to the molecular cluster particle size critical value corresponding to each pore diameter and all molecular cluster particle size data; Calculate the inaccessible pore volume IPV of the test reservoir according to the IPV value probability distribution law corresponding to each pore diameter data point and the IPV value corresponding to each pore diameter data point; When the interval and distribution frequency of pore diameter and the interval and distribution frequency of molecular cluster particle size are obtained through analysis, the inaccessible pore volume IPV is calculated as follows: According to the distribution frequency of each pore diameter interval, calculate the IPV value probability distribution law corresponding to each pore diameter interval; Calculate the IPV value corresponding to each pore diameter interval according to the critical value of the molecular cluster particle size interval corresponding to each pore aperture interval and the distribution frequency of all molecular cluster particle diameter intervals; According to the IPV value probability distribution law corresponding to each pore diameter interval and the IPV value corresponding to each pore diameter interval, calculate the inaccessible pore volume IPV of the test reservoir; When the distribution probability density function of the pore diameter and the distribution probability density function of the particle size of the molecular cluster are obtained through analysis, the inaccessible pore volume IPV is calculated as follows: According to the distribution probability density function of the pore diameter, calculate the IPV value probability density function corresponding to any pore diameter; According to the critical value of molecular cluster particle size corresponding to any pore size and the distribution probability density function of molecular cluster size, calculate the IPV value corresponding to any pore size; According to the IPV value probability density function corresponding to any pore diameter and the IPV value corresponding to any pore diameter, the inaccessible pore volume IPV of the test reservoir is calculated. 6. The reservoir inaccessible pore volume determining device as claimed in claim 5, wherein the inaccessible pore volume IPV calculation module is specifically used for: When all the pore size data after sorting and the particle size data of all molecular clusters after sorting are discrete, the inaccessible pore volume IPV is calculated using the following formula: Among them, N is the number of pore diameter data, i=1,2,...,N, a=1,2,...,N; x _i is the i-th pore diameter data; x _a is the a-th pore diameter data ; φ _i is the IPV value probability distribution law corresponding to the i-th pore diameter data; M is the number of molecular cluster particle size data; P _i is the IPV value corresponding to the i-th pore size data point; K _i is the serial number of the particle size critical value corresponding to the i-th pore size data point in all particle size data points ; IPV is the inaccessible pore volume IPV of the test reservoir. 7. The device for determining the inaccessible pore volume of a reservoir as claimed in claim 5, wherein the inaccessible pore volume IPV calculation module is specifically used for: When the interval and distribution frequency of pore diameter and the interval and distribution frequency of molecular cluster particle size are obtained through analysis, the inaccessible pore volume IPV is calculated by the following formula: Among them, N is the number of pore aperture intervals, i=1,2,…,N, a=1,2,…,N; x _i is the mean value data of the i pore aperture interval; x _a is the ath Pore diameter data; φ _i is the IPV value probability distribution law corresponding to the i-th pore diameter interval; f( _xi ) is the distribution frequency of the i-th pore size interval; M is the number of particle size intervals of molecular clusters; P _i is the IPV value corresponding to the i-th pore size interval; K _i is the corresponding The serial number of the particle size critical value in all particle size intervals; y _j is the mean data of the jth molecular cluster particle size interval; g(y _j ) is the distribution frequency of the jth molecular cluster particle size interval; IPV is the test The inaccessible pore volume IPV of the reservoir. 8. The device for determining the inaccessible pore volume of a reservoir as claimed in claim 5, wherein the inaccessible pore volume IPV calculation module is specifically used for: When the distribution probability density function of the pore diameter and the distribution probability density function of the particle size of the molecular cluster are obtained through analysis, the inaccessible pore volume IPV is calculated using the following formula: Among them, x is the pore diameter data, which is a continuous random variable; φ(x) is the probability density function of the IPV value of any pore diameter; [x _min , x _max ] is the range of the pore diameter; F(x) is the probability density function of the pore diameter within the range [x _min , x _max ]; P(x) is the IPV value of the pore with the pore diameter x; Ω (x) is the critical value of the molecular cluster particle size corresponding to the pore with the pore size x; G(y) is the probability density function of the molecular cluster particle size within the range [y _min , y _max ]; y is the molecular cluster particle size data, is a continuous random variable; IPV is the inaccessible pore volume IPV of the tested reservoir. 9. A computer device, comprising a memory, a processor, and a computer program stored on the memory and operable on the processor, characterized in that, when the processor executes the computer program, any one of claims 1 to 4 is realized. the method. 10. A computer-readable storage medium, wherein the computer-readable storage medium stores a computer program for executing the method according to any one of claims 1 to 4.